INDIANAPOLIS – For years the Indianapolis Colts have put the NFL’s slowest defense on its fastest playing surface. Does that sound stupid to you? Made sense to the Colts’ previous general manager and coach, who blew into town six years ago and installed on the fast turf of Lucas Oil Stadium the slower 3-4 defensive scheme – and compounded that mistake with players heavy on age, light on speed.

It evoked Einstein: his definition of insanity, doing the same thing over and over and expecting different results. I’m telling you this not to mock the folks who ran the Colts before, but to assure you the people running this franchise now, general manager Chris Ballard and the head coach he introduced on Tuesday, Frank Reich, will take the Colts’ 3-4 scheme from 2012-17 and put it where it belongs.

After the news conference Tuesday, Ballard was talking away from the podium when he said something startling: No NFL team whose home field is inside a dome has ever won the Super Bowl with a 3-4 defense. Research at pro-football-reference.com shows no team whose home field is inside a dome (or retractable roof) has reached the Super Bowl. See the point? On a fast surface, the best teams use the faster scheme. The 4-3 is faster, and I’ll dumb it down for you – OK, first I had to dumb it down for me – and explain why:

It’s math, and it’s simple. Each defensive front has seven players, obviously. The 3-4 has three down linemen and four linebackers. The 4-3 has four down, three up. Simple, right?

So is this: In a 3-4 the entire defensive front is enormous, another word for: slow. In that whole scheme, only two of those seven players – the outside linebackers – are pure speed guys. In the 4-3, the two defensive ends are smaller, faster. And the two outside linebackers are faster than the ends.

That’s four speed guys in one scheme, and two speed guys in the other, and remember that the Colts play eight games a year on the fastest turf in the league. This stuff is so obvious, I’m done wondering about the football IQ of the folks who used to run the Colts. I’m starting to wonder about your football IQ. And mine! Where were we when the Colts’ defense stunk six years in a row? Granted, some fans have clamored for the Colts to switch to a 4-3, but did anyone ever spell out the why as obviously as Ballard did?

No indoor team has ever won a Super Bowl with a 3-4 front.

Or as obviously as I just did?

On a fast surface, a scheme with four fast-guy positions sure seems smarter than a scheme with two fast-guy positions.

And let’s go ahead and talk about how fast this surface is. The fake stuff is always faster than natural grass, you know that, but not all fake stuff is created equal. There’s a reason NFL scouts love having the 2018 NFL Scouting Combine here: Prospects will run the 40-yard dash, and no facility is better at separating the fast from the blazing than this one. Five-time Pro Bowl outside linebacker Tamba Hali of the Kansas City Chiefs says Lucas Oil Stadium is the fastest field he’s played on. Chiefs safety Eric Berry called it “a fast surface, a thin surface … not the thick turf that you’re probably used to seeing” on other fields.

The down side to this switch, and there’s a down side to any undertaking this massive, is that the Colts don’t have the right personnel.

(Edwin Jackson, the sweetheart of a man who was killed last week by an alleged drunk driver, was one potential starter at inside linebacker. Rest in peace, “Pound Cake.”)

Indianapolis Colts head coach Frank Reich talks with former Colts Justin Snow and Hunter Smith, after a press conference introducing Reich as the new head coach of the Colts, at Lucas Oil Stadium in Indianapolis, Tuesday, Feb. 13, 2018. Jenna Watson/IndyStar

Indianapolis Colts general manager Chris Ballard speaks with media after a press conference introducing Frank Reich as the new head coach of the Indianapolis Colts, at Lucas Oil Stadium in Indianapolis, Tuesday, Feb. 13, 2018. Jenna Watson/IndyStar

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As they are currently constructed, the Colts are set only at the two interior defensive tackle positions in the 4-3 front. Johnathan Hankins, Henry Anderson, Al Woods and Hassan Ridgeway make for a fine rotation. The 6-6, 290-pound Anderson also could get looks at defensive end, but only the freakiest of men built his size (Jacksonville’s 6-8, 282-pound Calais Campbell comes to mind) belong at defensive end in a 4-3. More likely, from the entire Colts 2017 roster, only Jabaal Sheard (a 6-2, 254-pound OLB in the 3-4) looks capable of playing end in the 4-3.

In other words: The Colts’ seven-man defensive front will need an overhaul at four or five positions thanks to this move to the 4-3. Then again, it needed an overhaul at most spots anyway. This defense was 30th in the NFL in points and yards allowed. The roster Ballard inherited before the 2017 season was big and slow and sloppy, built for road games in the AFC North at Pittsburgh, Baltimore, Cleveland and Cincinnati.

Thing is, the Colts are in the AFC South. They play indoors. So does Houston. Weather in Nashville can go either way, but it’s usually going to be warm in Jacksonville. The better the weather, the faster the game.

Frank Reich gets it. His Eagles just won a Super Bowl with a 4-3 defense, and he was fine when told that his defensive coordinator – Matt Eberflus, formerly the linebackers coach in Dallas – already had been hired, and the 4-3 scheme chosen.

“I’ve had the chance to talk with Matt at some length,” Reich was saying Tuesday of Eberflus. “This is like a home run.”

Ballard said the 4-3 scheme “fits our building. We’re playing on an indoor surface. We’re going to be playing in ideal weather 8-12 games a year.”

And those games, Ballard went on to say, will “be based on athletic ability and speed.”

Sounds so simple, doesn’t it? Under GM Bill Polian and coach Tony Dungy, Robert Mathis and Dwight Freeney were Hall of Fame defensive ends in the 4-3, and 2006 Super Bowl champions to boot. Under the folks who blew into town in 2012, they were moved to outside linebacker. After averaging 10 sacks per season for a decade in the 4-3, Freeney disappeared in the 3-4 (five sacks in 2012) and then left. Mathis had an epic 2012 (19.5 sacks), but was never again effective. Pass-rushing savant Robert Mathis, coming back from a torn Achilles’ tendon, was being asked to drop back into coverage in 2014 and ‘15. It was hard to watch.

No, it was stupid, what the Colts were doing on defense from 2012-17. Stupid and lousy. What they’ll do on defense going forward might not be initially better – the roster churn will take a year or two – but at least it will make sense. The Colts will try to put a fast defense on their fast field.

Not exactly rocket science. But not the remedial defense we’ve seen around here for too long.